Global navigation satellite devices, also referred to as global navigation satellite systems (GNSS), calculate the position of a receiver terminal by measuring the propagation time of signals emitted by navigation satellites between the satellites and the receiver terminal. The terminal then deduces therefrom the distances between the various satellites and the terminal.
Because the signal passes through the various layers of the atmosphere, the position estimated by the terminal is not always exact. It is known to introduce corrections into the system of calculations so as to account for this interference but the models used are complicated to define. In addition these models do not take into account the environment of the receiver terminal, such as multipath effects for example.